Direction finder installation



Aug. 24, 1954 A. TRoosT 2,687,521

DIRECTION FINDER INSTALLATION Filed Oct. 25, 1951 IMO/6476'? L4 l J INVENTOR.

ALBERT TR 00 ST" Patented Aug. 24, 1954 v NT OFFICE DIRECTION FINDER INSTALLATION Albert Troost,-'Ulm (Donau), Germany,

assignor to Telefunken Gesellschaft fuer drahtlose Telegraphic G.

m. b. H., Stuttgart,

Germany Application October 23, 1951-, Serial No. 2 52,663

Claims priority, application Germany I October 30, 1950 Claims. (Cl. 343'-113) The present invention relates to a direction finder installation and a method for ascertaining the operating condition of the parts thereof.

It is an object of the present invention to facilitate a checking of the operating condition of the parts of a direction finder installation.

It is another object of the present invention to ascertain faults in the directional antennas or in the connections thereof.

' It is a further object of the present invention to ascertain a break or a short-circuit in the connections to the directional antennas.

It is a still further object of the present invention to ascertain faults of the kind described at the place of the operator which, as a rule, is remote from the directional antennas.

A method according to the present invention comprises in its broadest aspects the steps of generating a high frequency voltage, and coupling the high frequency voltage to the parts of the direction finder installation.

In a preferred embodiment of the present invention a harmonic, preferably the third harmonic, is filtered out of the high frequency voltage and coupled to the parts er installation. A direction finder installation according to the present invention comprises in combination a plurality of directional antennas arranged symmetrically with respect to one another, a goniometer having a plurality of stationary windings arranged symmetrically with respect to one another and being connected, respectively, to the directional antennas, a rotatable winding forming part of the goniometer, means for locally generating a high frequency voltage, andswitching means for connecting the stationary windings simultaneously to the generating means whereby the high frequency voltage is applied by the switching means simultaneously to the stationary windings and the directional antennas connected therewith so that the operative condition thereof can be ascertained by rotating the rotatable winding of the goniometer into a position v of extremal current response.

In a preferred embodiment of the present invention an amplifier including an oscillating stage is connected to the rotatable winding of the goniometer and the high frequency is generated in the oscillating stage of the amplifier.

Preferably the switching means include stationary contacts connected, respectively, to the terminals of the stationary windings, and movable contacts connected to the oscillating stage of the amplifier. '"Preferably"condensers are in of the direction findmovable contacts l2 stationary contact IZa" 'serted, respectively, between the stationarycontacts and the terminals of the stationarywind- I The novel features which are considered as characteristicforthe invention are set forth'in particular in the appended claims. The invention itself,however, both as to its construction and its method of operation,. together with additionaltobjects and advantagesthereof, will be best understood from the following, description of specific embodiments when readin connection withthe accompanying drawings, in which: Theonly'figure is; a wiring-diagram showing the essential parts of a direction finder installation according to the present invention.

Referring now to the drawing, thedirection finder installation comprises a plurality, preferably two directional antennas l and 2 such as frames or loops which include with each other an angle of 90. The "antennas l and 2 are connected, respectively, over two cables 3 and 4 to the stationary field windings 5 and Bof a goniometer which include an angle of 90 with each other. The rotatable winding I of the goniometer is connected to the tuning condenser 8 which is connectedbetween a cathodeand the grid of the first tube 9"of an amplifier. The cables 3 and 4 are only-diagrammatically indicated in the drawing, andit should be understood'that the directional antennas or loops [and 2 .can be arranged remote from the goniometer, the cables 3 and 4 having in this case' a considerable length. It! is an oscillating or mixing stage, preferably the second oscillator ormixer of the amplifier the first tube 9 of which is connected'to' the tuning condenser E and the rotatable winding 1 of the goniometeiz- Theoscillating or mixing stage logenerates a high frequency voltage having as a rule a frequency of kilocycles per'second which is-appliedto a cable! I connected to the movable contacts l2 and I2" of a switch [2 which is preferably a two-pole double-throw switch having stationary contacts I 2a, IZb, l2a" l2b-cooperating,' respectively, with. the and I2". The stationary contact l2a' is connected over a condenser 15 to one terminalof the stationary winding 5, the other terminal of which is connected to the stationary contact 121) over'a condenser l3. The

ing 6, the other terminal of which is connected to the stationary contact l2b" over a condenser I4.

- As already mentionedflube' 9 is the input stage is connected over a condenser IE to one terminal of the stationary wind of the amplifier.

fiers is indicated by the dashed block 18. The

, output of the amplifier is supplied to an indicator I9 which may be any type of indicator known in the art. The entire arrangement including stage 9, oscillator l0, amplifier l8 and indicator l9 comprise the indicator means I! which is connected to the rotatable winding 1 of the goniometer.

Instead of capacitively coupling the high frequency voltage to the stationary windings 5 and 6 an inductive coupling could be provided. Also, the high frequency voltage could be coupled with the directional antennas by a system of conductors consisting of two coils arranged at right angles to each other and symmetrically with respect to the directional antennas.

The operation of this device is as follows:

If it is intended to ascertain the operative condition of the parts of the direction finder installation, and more particularly ofthe directional antennas I and 2, the cables 3 and 4, and the stationary windings 5 and 6, the switch I2 is closed either to make contact with the stationary contacts Ma and 12a or with the stationary contacts l2b' and I21)". In either case the high frequency voltage generated by the oscillating stage l of the amplifier is coupled with the stationary windings and 6, the cables 3 and 4 and the directional antennas l and 2.

Preferably the receiver of the direction finder installation is tuned to a harmonic, preferably the third harmonic, of the high frequency voltage generated by the second oscillating or mixing stage In. Then the rotatable winding is rotated until an extremal, i. e. a minimum or maximum current response is obtained. If all the parts of the direction finder installation are in good operative condition the extremal, i. e. the maximum or minimum current response of the rotating winding will occur when the latter includes an angle of 45 with each of the stationary windings 5, 6 because in this case the stationary windings are excited equally by the high frequency voltage or the harmonic thereof. If, however, an asymmetry exists, for instance, by the break of aconductor or by a short-circuit, even a high'ohmic short-circuit which can be caused by water entering one or both of the cables 3 and 4, the angle deviates from 45, a deviation to one sideindicating a break of a connection and a deviation to the other side indicating a shortcircuit. Therefore such faults are rendered easily recognizable. It should be noted that a particular advantage of the present invention consists in that faults of the direction finder installation can be recognized at the working place of the person operating the goniometer so that the operator has not to go as far as the remote place of the directional antennas l and 2.

The two positions l2 are provided in order to ascertain faults caused by a defect of parts of the stationary windings 5. and/or 6 of the goniometer.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of methods for ascertaining the operative condition of the parts of a direction .finder installation differing from the types described above.

While the invention has been illustrated and described as embodied in a direction finder in,-

stallation, it is not intended to be limited tov the details shown, since various modifications and of the double-throw switch structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt ting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended withinthe mean- N ing and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a direction finder installation, in combination, a plurality of directional antennas arranged symmetrically with respect to one another; a goniometer having a plurality of stationary windings arranged. symmetrically with respect to one another and connected, respectively, to said directional antennas; a rotatable winding forming part of said goniometer, said goniometer being arranged remote from said directional antennas; connections connecting, respec-r tively, said stationary windings of said goniometer with said directional antennas; an amplifier connected to said rotatable winding of said goniometer, said amplifier including an oscillating stage;

- means for generating a high frequency voltage in stationary windings, and movable contacts connected tosai d oscillating stage of said amplifier; and condensers inserted, respectively, between said stationary contacts and the terminals of said stationary windings whereby the high frequency voltage is applied by said switching means simultaneously to said stationary windings and said directional antennas connected therewith so that the operative condition thereof can be ascertained by rotating said rotatable winding of said goniometer into a position of extreme current response.

2. A system for testing the performance of a direction finder installation including a first and a seconddirective antenna arranged symmetricallywith respect to each other, a goniometer having a pair of relatively stationary windings connected to said first and said second antenna, respectively, as well as a third winding movable with respect to said pair of windings, and indicatOr means. connected to said third winding; said system comprising a local source of high frequency voltage and connecting means for irne pressing said high-frequency voltage simultaneously upon both of said stationary windings and both of said antennas, thereby producing in said goniometer an electro-magnetic field whose. direction, as ascertained through said indicator means upon rotation of said third winding, is

dependent upon the relative impedances of said eally with respect to each other,-a goniometer having a pair of relatively stationary windings it for various applications without omitconnected to said first and said second antenna, respectively, as well as a third winding movable with respect to said pair of windings, and indicator means connected to said third winding; saidsystem comprising a local source of highfrequencyvoltage and connecting means for impressing said high-frequency voltage upon a portion of each of said stationary windings and in bucking: relation thereto upon another portion ofeach of said stationary windings in series with the respective one of said antennas, thereby pro-.

ducing in said goniometer an electromagnetic 'field whose direction, as ascertained through said indicator means upon rotation of said third winding, is dependent upon the relative impedances of said stationary windings and said antennas, whereby a departure of any of said impedances from normal may be determined from a deviation of said field from a predetermined orientation.

I -4. A system for testing the performance of a direction finder installation including a first and a second directive antenna arranged symmetrically with respect to each other, a goniometer having a pair of relatively stationary windings connected across said first and said second antenna, respectively, as well as a winding movable with respect to said pair of windings, and indicator means connected to said third winding; said system comprising a local source of high-frequency voltage and circuit means for connecting said source between the midpoint of each of said stationary windings and a point intermediate each stationary winding and the respective antenna, thereby producing in said goniometer an electromagnetic field whose direction, as ascertained through said indicator means upon rotation of said third winding, is dependent upon the relative impedances of said stationary windings and said antennas, whereby a departure of any of said impedances from normal may be determined from a deviation of said field from a predetermined orientation.

5. A system for testing the performance of a direction finder installation including a first and a second directive antenna arranged symmetrically with respect to each other, a goniometer having a pair of relatively stationary windings connected across said first and said second antenna, respectively, as well as a third winding movable with respect to said pair of windings, and

indicator means connected to said third winding;-

said system comprising a local source of highfrequency voltage, circuit means connecting an output terminal of said source to the midpoint of each of said stationary windings, and switch means for connecting another output terminal of said source selectively to a point intermediate each antenna and either half of the respective stationary windings, thereby producing in said goniometer an electromagnetic field whose direction, as ascertained through said indicator means upon rotation of said winding, is dependent upon the relative impedance of said stationary windings and said antennas, whereby the presence of a defect in either of said stationary windings and antennas may be determined from a deviation of said field from a predetermined orientation, operation of said switch means to reverse the connection between said source and said winding halves enabling identification of the defective antenna or winding half.

6. In a direction finder installation, in combination, a first and a second directive antenna arranged symmetrically with respect to each otherya-gohiometer having a pair of relatively ing, is'dependent upon the relative impedances of said stationary windings and said antennas, whereby a departure of any of said impedances from normal may be determined from a deviation of'said field froma-predetermined orientation. '7. In a direction finder installation, in combination, a first and a second directive antenna arranged symmetrically with respect to each other; a goniometer having a pair of relatively stationary windings connected to said first and said second antenna, respectively, as well as a third winding movable with respect to said pair of win-dings; indicator'means connected to said third winding, said indicator means including an amplifier provided with a mixing stage, oscillator means in said mixing stage, and an input circuit for said amplifier tuned to a harmonic of the output of said oscillator means; and circuit means connecting said oscillator means to both of said stationary windings and both of said antennas in a manner producing in said goniometer an electromagnetic field whose direction, as ascertained through said indicator means upon rotation of said third winding, is dependent upon the relative impedances of said stationary windings and said antennas, whereby a departure of any of said impedances from normal may be determined from a deviation of said field from a predetermined orientation.

8. A method of testing the performance of a direction finder installation including a first and a second directive antenna arranged symmetrically with respect to each other, a goniometer having a pair of relatively stationary windings connected to said first and said second antenna, respectively, as Well as a third winding movable with respect to said pair of windings, and indicator means connected to said third winding; said method comprising the steps of locally generating a high-frequency voltage, applying said voltage simultaneously to both of said stationary windings and both of said antennas in a manner producing in said goniometer an electromagneticfield whose direction is dependent upon the relative impedances of said stationary windings and said antennas, and determining the orientation of said field by rotating said third winding to a position of extreme response of said indicator means.

9. A method of testing the performance of a direction finder installation including a first and a second directive antenna arranged symmetrically with respect to each other, a goniometer having" a pair of relatively stationary windings connected to said first and said second antenna,

respectively, as well as a third winding movable with respect to said pair of windings, and indicator means connected to said third winding;

said method comprising the steps of locally generating a high-frequency voltage producing a first magnetic field in each of said stationary windings by applying said voltage to a portion thereof, simultaneously producing a second mag-' netic field or" different magnitude from said first field, and in bucking relation thereto, in each of said stationary windings by applying said voltage to another portion therof in series with the respective antenna, and determining theexistence of any cit-normal orientation of the resultin magnetic field by rotating said third winding to a position of extreme response of said indicator means. d v r I 10. A method of testing the performance of a direction finder installation including a first and a second directive antenna arranged symmetrioally with respect having a pair of ary windings by applying said voltage to the other half of each of said stationary windings in series with the respective antenna,

orientatio treme res ing said rotating said third noting the n of the resulting magnetic field by winding to a position of exponse of said indicator means, applyvoltage directly to said other half of each of said stationary windings and, simultaneously therewith, to said one half of each of said antenna, magnetic stationary windings in series with said respective noting the orientation of the resulting fieldby rotating said third Winding to a position of extreme response of said indicator means, and comparing said orientations with direction.

each other and'with a predetermined reference References Cited in the file of this patent Number 25 acoust- UNITED STATES PATENTS Name Date Browning Apr. 26, 1949 Cleaver June 6, 1950 OBrien Jan. 15', 1952 Goldstein Aug. 12,1952 

